package company.zuiyou;

import java.util.Scanner;

public class Z2 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        System.out.println(helper(n));
    }

    public static int helper(int n) {
        if (n == 0)
            return 0;
        else if (n == 1)
            return 1;
        int[] dp = new int[n + 1];
        dp[0] = 1;
        dp[1] = 1;
        for (int i = 2; i <= n; i++) {
            int sum = 0;
            //j表示起始位置
            for (int j = 1; j <= i; j++) {
                // 左子树 * 右子树
                sum += dp[j - 1] * dp[i - j];
            }
            dp[i] = sum;
        }
        return dp[n];
    }
}
